Laserfiche WebLink
® WorleyParsons <br /> resources&energy <br /> • Equipment will be sized to handle the maximum required current. The unit auxiliary <br /> transformers, 4160V equipment, and 480V switchgear will all be sized to handle the <br /> load of the entire plant configuration. <br /> • Equipment short-circuit ratings will be based on the maximum short-circuit currents <br /> under all operating conditions and will take into account equipment design margins. <br /> There are no provisions for future loads. <br /> • Motors greater than 200 hp will be supplied from the 4160V system. Motor-operated <br /> valves and motors from 3/4 hp up to and including 200 hp will be supplied from the <br /> 480V system. Motors less than 3/4 hp will be fed from the 120V system. <br /> • The electrical power distribution system design and cable sizing will be selected to <br /> limit the cable voltage drop from source to load to not more than 5 percent. The <br /> allowable voltage variation at the load equipment will be limited to +10 percent of the <br /> load nominal voltage rating under normal continuous operating conditions. The <br /> electrical system design will also be based on motor starting and system capability <br /> requirements. <br /> • Electrical and controls equipment requiring access for normal operation and/or <br /> maintenance will be accessible from permanent floors or platforms without scaffolding, <br /> portable ladders, or lifts. Access space and clearance for electrical equipment will be <br /> per manufacturer's recommendation and in accordance with NEC requirements. <br /> 4.3 Plant DC Power Systems <br /> Plant DC will be supplied from 125VDC and 24VDC battery systems. Emergency power <br /> for the CTG critical loads will be supplied by the 125VDC battery system supplied with <br /> each CTG. Control power for the plant electrical equipment, e.g. switchgear will be <br /> supplied by the station 125VDC battery system. <br /> The station 125VDC system will consist of one (1), 100% capacity battery bank, two 100% <br /> capacity battery chargers, battery management system, a switchboard, and the required <br /> 125VDC panelboards. The batteries will be lead-acid. This system will supply DC power <br /> requirements for the uninterruptible power supply (UPS) system, medium and low voltage <br /> switchgear, balance of plant, and any critical DC loads. The station 125VDC system will <br /> be sized to supply the plant emergency loads for a period long enough to allow a safe <br /> shutdown of all plant equipment including the CTG, gas compressor, etc. The battery will <br /> be sized in accordance with IEEE 485. Battery racks will be designed to applicable project <br /> specific seismic zone requirements. <br /> Each battery charger will be sized to supply the normal DC loads while simultaneously <br /> recharging a fully discharged battery in twelve (12) hours or less. Each charger will be <br /> designed such that it may be operated as a battery eliminator with the battery disconnected. <br /> The batteries will be connected to the DC switchboard through a disconnect switch. The <br /> switchboard and panelboards will be designed for indoor installation and constructed in <br /> accordance with NEMA PB-1 and PB-2. Each panelboard will be provided with 20 percent <br /> Lodi Energy Center 3.4-2 LEC AFC <br /> 071608 Rev.A <br />